Sherwin Carlquist

Learn More
-A hitherto unappreciated correlation exists between nature of vessel grouping and nature of imperforate tracheary elements in wood of dicotyledons at large: families and genera with true tracheids (large fully bordered pits common on both radial and tangential walls) have solitary vessels. Presence of true tracheids as a subsidiary conductive system is(More)
Current definitions of tracheids and vessel elements are overly simple. These definitions are based on light microscope studies and have not incorporated information gained with scanning electron microscopy (SEM) or transmission electron microscopy (TEM). Current definitions are based primarily on angiosperms, especially eudicots, and were devised before(More)
This species, which is quite similar in habit to A. nummularia Torr., is new to Texas. According to Woodson (in Ann. Mo. Bot. Gard. 41 : 94. 1954), this northcentral Mexican species was previously known to occur in the United States only in southern New Mexico. It is of interest to note that in addition to the Mexican states of Coahuila, San Luis Potosi and(More)
Ferns in which vessels have been demonstrated to date are phylogenetically relatively specialized and characteristic of habitats with marked extremes in temperature and water availability. These specifications do not apply to the Gleicheniaceae, which indicates that vessels may occur in a range of more primitive ferns, including those from more nearly mesic(More)
Eight wood samples representing six species in two genera of Scytopetalaceae are examined with respect to qualitative and quantitative features. Rhaptopetalum differs from Scytopetalum by having scaJariform perforation plates, fiber-tracheids, longer vessel clements, and a series of features probably related to the understory status of Rhaptopetalum is(More)
Xylem of the orchids studied provided unusually favorable material to demonstrate how conductive tissue evolves in monocotyledons. In the end walls of tracheary elements of many Orchidaceae, remnants of pit membranes were observed with scanning electron microscopy and minimally destructive methods. The full range from tracheids to vessel elements, featuring(More)
We have studied macerated xylem of ferns, supplemented by sections, by means of scanning electron microscopy (SEM) in a series of 20 papers, the results of which are summarized and interpreted here. Studies were based mostly on macerations, but also on some sections; these methods should be supplemented by other methods to confirm or modify the findings(More)